摘要
合成了单核二氧大环四胺镍(Ⅱ)配合物,对该配合物在不同胶束体系中催化对硝基苯基α吡啶甲酸酯(PNPP)的水解进行了动力学研究,用三元复合物动力学模型处理得到了相关的动力学和热力学参数.结果表明,该配合物对PNPP水解反应有显著的催化作用,配合物在两性离子表面活性剂正月桂酸肌氨酸钠(LSS)和非离子表面活性剂聚氧乙烯(23)十二烷基醚(Brij35)胶束溶液中对PNPP水解的催化活性高于在阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)胶束溶液中的催化活性;配合物的空间构型对反应速率有较大影响,具有四面体结构的配合物更有利于PNPP的水解.
The hydrolysis of p-nitrophenyl picolinate (PNPP) catalyzed by Ni(Ⅱ) dioxocylam complexes was investigated kinetically by observing the release rate of p-nitrophenol in different micellar solutions. The ternary complex kinetic model for metallomicellar catalysis was employed to obtain the relative kinetic and thermodynamic parameters, including the first-order rate constant (k) and association constant (K) for ternary complex. Compared with the spontaneous hydrolysis of PNPP, the reaction rate for catalytic hydrolysis of PNPP increased by a factor about 3?000 . The effects of different surfactant micelles on the catalytic hydrolysis of PNPP followed the order n-lauroylsarcosine sodium (LSS)>polyoxyethylene(23) lauryl ether (Brij35)>hexadecyltrimethyl-ammonium bromide (CTAB), which may be due to the electrostatic effect and hydrophobic effect between the reactant and micelles. The hydrolysis of PNPP catalyzed by the complex followed the mechanism in which the intramolecular nucleophilic attack of nickel-bounded hydroxide on carbonyl carbon of PNPP was involved. In addition, the complexes with tetrahedral structure would accelerate the hydrolysis of PNPP.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第7期602-608,共7页
基金
国家自然科学基金资助项目(20173038
20107004).
